Question 819915: Frankie drove from San Antonio to her friend's in Austin, a distance of 75 mi. She visited for 2 hours before continuing on to Dallas, another 195 mi. If she drove 10mph faster between San Antonio and Austin, than between Austin and Dallas, and the time between when she left San Antonio and arrived in Dallas was 6hr, what was her average speed between San Antonio and Austin?
must be solved algebraically
Answer by richwmiller(17219)   (Show Source):
You can put this solution on YOUR website! we need to find the total time and distance
we know it took her 6 hours and she went 75+195=270
mph= 270/6=45 mph average speed from san antonio to dallas
but we want to know from san antonio to austin
6-2=4 hours actual traveling time
(r+10)*t=75,
r*(4-t)=195
r = 65, t = 1
r+10=75 mph from san antonio to austin
1+2+3=6
she took three hours at 65 mph to get from austin to dallas.
3*65=195
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